Ignition magneto



April.;'l8, 1939. f U, QU|NTAVALLE IGNITION MAGNET() y Filed sept. 25, 1936 I M IL l WWW! Patented Apr. 18, 1939 uNlTEfo-" y Y Application r-f'his invention relates to the,I.formation ofthe parts of the magnetic circuitor path in magnetoelectric ignition devices in which pole members are embedded in a cast body, and said pole membersform pole shoes andarmsextending from saidpole shoes having a. reducedA thickness with respectto said pole shoes. .Y o Y The present invention includes theprovision of a magnetic circuit or path by locating astack of superimposed iron sheets o r laminations for each pole of sadcircuit in themould. where the body of the apparatus is cast and then the excess portions of said sheets or laminationsare subsequently trimmed oiby machining.

arms extending therefrom, preferably comprisv ing sheets.. Eachsheet includes alrportion intended to form the pole'shoe andnonA one side thereof, a tongue having a width `smaller than v the length of the pole shoe. 'Ihe adjacent sheets of the stack have their tongues staggered-or offset with 'respect to one another to forlnvin their entirety an arm having a reduced".` thickness. and a side surfaceA of sui table .extent for the connection of said larm withother parts of the Vmagnetic circuit( y The above `outlined arrangement is-.ot advantage when-saidarms are tofbe connected with the ends of the core of a winding located intermediate them, because the reduced thickness of saidvarms secures a maximum 'space available for said winding within a given overall size of the whole, and a proper area for the surface on which said core .and arms contact with each other. A

' further advantage is secured by the fact that all the sets of sheets of the pole members are in direct contact with the winding core.

On the annexed drawing an embodiment of this invention is illustrated by way of example,

and

Figure 1 is a fragmentary longitudinal section of a portion of the body cfa magneto electric ignition apparatus with parts removed on section line I-I of Fig. 2;

Figure 2 is a transverse section on line 2- 2 of Fig. 1; Y

Figure 3 is a separate perspective view of a stack of iron sheets or laminations forming a pole piece which has a pole shoe and an arm;

.Figure 4shows separately one of the sheets forming the stack shown in Figure 3, on a reduced scale;

' 5 shows separately another one oi' the sheets forming the stack shown in Figure 3, on

55 a. reduced scale;

Each stack intended to form a; 'pole'f piece Vhas l Aottime arm of a polemember as obtained after the sheets forming saidpolemember have been superimposed, andl Figui-e 'Lis asimilar section after said staclr.

,hasv subjected to ank operation to 'reduce the thickness ofA therarm of the pole. member. In the illustrated construction the `magnetic circuitv whichl is assumedto belonglto an ignition magneto for internal-combustion engines andv in. o

whichz theparts'ofvsaid magneto. which are not ,drectlyuinvolved in the present invention are omitted,l inc1udesfourpo1e-faces I II, I0,2 0, v2li .provided by two-pairs of-pole'me'mbers I, Zand .I"-, l2' located .in-front of each-other in` pairs and a core 8 having a winding 9 thereon' and con` nected with, said.. pole members as, hereinafter 'described The pole .members are engaged in the requisiterespective "position in the, ybody 3- by -casing 4them torfbe-embedded infthemass'of For such a purpose fl-orming thev several polemembers areflocated in the mouldintended for casting said. without` vFigure .Gis arzdiagrmmatic transverse section interconnecting'them. and then metal 'is'. pouredv fin mould tonrforrn saidbody 3 and embed said sheetQstacks therein.

Eachl of theA poler members I, I' comprises superimposed iron sheets or laminati'ohs (Fig. 3) .forming a staclc and may be interconnected by fmeans of bolts, screws, rivets or. in any preferred .mannen `'I'l'ie sheets or la'minationsv include each a portion Ia which extends in adirection parallel to the axis of the space vfor the magneto rotor intermediate said pole shoes, as well as portions Ib, Ic as hereinafter described, forming in their whole a side arm 5 or 5', in respect of pole mem-r ber I or I' respectively, intended to provide a portion of the magnetic circuit or path.

To form the arms 5, 5' each sheet of thepole members I, I' includes a narrow tongue, as Ib or I c, extending from said portion I-a. Each of the arms is, thus connected with the respective pole shoe only along a portion of the longitudinal extent of the same.

In order that the arms 5, 5' of the pole members I, I may have each a reduced thickness withA respect to the associate pole shoe I, two sets of sheets are used to form each pole member. The sheets all have a general L-shape but a respective different configuration. The sheets are shown separately and referenced by 6 and 1 each in its whole in Figs. 4 and 5 Where the portions Ia thereof providing a pole shoe as I are shown and IIb, Ic are the tongues intended to form an arm as 5. Such tongues extend transversely from the respective portions Ia and have a restricted size in the direction in which the length oi portions Ia extends. Further, said tongues Ib, Ic have a staggered or offset position along the extent of portions Ia of the respective sheets. The portions la are identical in all the sheets of both sets and sheets of different sets. In other words sheets o! the type of Figures 4 and 5 respectively, alternate in each stack to cause said tongues Ib, Ic to be adjacent to each other but staggered or oii'set in the direction of the thickness of the arm 5 or 5', as shown in Figure 6.

Thus in each stack the portion thereof forming an arm as 5 or 5,' has a width, that is a size in the direction in which pole shoe portions Ia extend, which is the sum of the widths of tongues Ib, Ic while the actual or total thickness of iron laminations or sheets in each arm is one half of the thickness of pole shoe I that is oi the thickness pertaining to the number of sheets forming the stackand pole shoe I.

The thickness of the arm 5, l of each pole member may thus be made smaller than the thickness of the pole shoe I by compressing or collapsing said stack in the region thereof forming said arm. Such operation may be carried out by bending tongues Ib, Ic where they connect with portions Ia oi' the respective sheets to impart to the pole members the shape shown in Figures 2 and 3 where the tongues Ib, Ic of each set approach each other and form a coherent piece 5 or 5' whose thickness (as shown in Figure 7) is one half of the initial one (Figure 6).

On the other hand by imparting a proper width to tongues Ib, Ic in the direction oi the longitudinal extent of the portions Ia of the respective sheets, the requisite width may be imparted to the faces of the arms s, s' and both sets of sheets Ia, Ib and Ia, Ic partake directly in the formation of said arms.

'I'hus the overall size and weight of the magnetic circuit are reduced and the operative conditions of said circuit are improved, particularly when all the sheets of the pole member are required to connect directly with another member oi the magnetic circuit as a core l of a winding 9.

'I'he pole members 2 and 2 consist each of a stack of iron sheets and they are interconnected with respective pole members I and I by suitable cross bridges 4, 4.

The sheets Ia, Ib and Ia, Ic may have a different configuration with respect to the illustrated ones and more particularly their tongues Ib, Ic may have a non-rectilinear coniiguration and/or extend at an angle different from a right angle with respect to the respective portion pertaining to the pole shoe I.

Further, a larger number of sets of sheets as 6, I than two may be used with the sheets of the several sets Ahaving then such a configuration of the tongues as Ib, Ic that the sheets of several types are staggered or offset longitudinally of the respective pole shoes after they have been piled up in a stack.

What I claim as my invention and desire to secure by U. S. Letters Patent is:

1. In an ignition magneto a pole member comprising a stack oi sheets each having a portion to form a pole shoe and a tongue, said sheets being superimposed with said pole shoe portions adiacent one another and said tongues oii'set from one another in adjacent sheets, said tongues being bent into contact with one another to form a pole arm having a reduced thickness with respect to said pole shoe.

2. In an ignition magneto, a pole member comprising a stack of sheets each having a portion to form a pole shoe and a portion to form a tongue, said sheets being superimposed with said pole shoe portions adjacent one another and said tongues being offset from one another in adjacent sheets, said tongues being deformed to provide a pole arm oi less thickness than said pole shoe.

3. In an ignition magneto, a pole member comprising a stack of sheets each including a portion substantially equal in all said sheets to form a pole shoe and a tongue to form a pole arm, said sheets being superimposed with said pole shoe portions together and said tongues offset from one another in adjacent sheets, said tongues being bent in contact with each other to provide a pole arm having a reduced thickness with respect to said pole shoe. 1

4. In an ignition magneto a pole member comprising a stack of sheets each including a portion to form a pole shoe and a tongue, said sheets being superimposed with said pole shoe portions coincident and said tongues offset i'rom one another in alternate sheets, the superimposed tongues being bent in contact with each other to form a pole arm having a reduced thickness with respect to said pole shoe.

UMBERTO QUINTAVALLE. 

